Leak resistant battery cover

ABSTRACT

The present invention is directed to a leak resistant battery cover for storage batteries. The battery cover provides a labyrinth of passages which provide a path from each cell vent to the atmospheric vent. The labyrinth is configured to provide a portion of each path above a level in which the electrolyte in the respective cells attains when the battery is tipped on any one of its sides or rotated ninety (90) degrees from an upright position. The labyrinth configuration prevents electrolyte from reaching the atmospheric vent and spilling out of the battery.

This application is a continuation of application No. 08/796,423, filedFeb. 6, 1997, now U.S. Pat. No. 5,683,830.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to a storage battery cover, and more particularlyto a storage battery cover offering added protection against leakagewhen a battery using the cover of the invention is tipped to any one ofits sides or inverted.

(2) Description of the Prior Art

Conventional storage batteries include a battery housing having ahousing and a cover for closing an open top end of the casing. Thebattery housing is a rectangular casing having multiple compartments orcells for receiving cell plates and electrolyte therein. The coverdevice is heat sealed to an open top end of the battery housing casing.

The cover device often includes a main cover part and a sub-cover part.The main cover part has a horizontally disposed plate body with a topface formed by a rectangular confining wall. The confining wall isdivided by multiple partitions and associated chambers. The main coverfurther includes multiple service ports for pouring electrolyte intorespective cell compartments within the casing and multiple degassingvents and drain-back return holes associated with each cell.

The sub-cover is integrally secured to the main cover after electrolytehas been poured into the cell compartments through the service ports.The sub-cover part is heat sealed to the main cover part along itsperimeter and at top edges of the partitions and chamber walls. Thechambers and partitions ultimately form enclosed chambers and associatedpaths from the cell vent and return hole of each cell to multipleatmospheric vents. The chambers typically include relatively largecontainment areas for holding electrolyte spilled into the battery coverwhen the battery is tipped.

In operation, heat that is generated during electrolysis causes theelectrolyte and water in the electrolyte to evaporate. This evaporationis referred to as “gassing”. Gassing of the cells occurs at any pointthe battery reaches the hydrogen over-voltage, producing bubbles thatbreak at the surface introducing a mist into the venting gas stream. Inconventional batteries, the vaporized electrolyte was released toatmosphere through an atmospheric vent in the cover device. Loss ofelectrolyte through the atmospheric vent requires replenishingelectrolyte in the battery housing periodically. In order to overcomeelectrolyte loss, a battery housing with a cover capable of recoveringthe vaporized electrolyte was developed, thereby obviating the need forreplenishing the electrolyte in the battery housing.

When the electrolyte in the cell compartments undergo electrolysis andevaporates due to the heat that is generated, the vaporized electrolyteflows into the path formed in the cover through the cell vents ordrain-back holes. Since the interior of the cover is exposed to theatmosphere via the atmospheric vent, the interior temperature of thecover is less than that of the vaporized electrolyte entering the cover.Thus, heat transfer occurs so that the vaporized electrolyte condenses,and the resulting condensate flows back into the corresponding cellcompartments via the drain-back holes. The paths are often slopedtowards the drain-back holes to further facilitate the return ofelectrolyte to the respective cells. Since the vaporized electrolyte isrecovered instead of released to atmosphere, there is no need toperiodically replenish the electrolyte in the battery housing.

Although these batteries prevent electrolyte loss during normaloperation, the battery will leak, and in many cases pour, electrolytefrom the atmospheric vents when the battery is tipped to one side,inverted or agitated. Batteries are often placed in a non-uprightposition during shipping, handling or accidents, such as car wrecks. Asignificant threat to person and property arises when electrolyte leaksfrom a battery.

Various approaches have been taken in the past to deal with the problemof electrolyte spilling or leaking from a battery when it is tipped toany one of its sides. Many of the arrangements are acceptable insituations where the battery is tilted to its side and not subjected tovibration or other forms of movement. However, the related art has yetprovided a cost effective battery cover providing total steady stateleak protection when the battery is tipped to one side and substantialresistance to electrolyte leakage when subjected to vibration, agitationor inversion.

U.S. Pat. No. 1,605,820 to Edwards discloses a multilevel chamberconfiguration for each cell. The chamber includes two opposed inclinedpartitions for preventing electrolyte spills when the battery is tippedto one side. The chamber configuration provides no inverted leakprotection. Furthermore, the large chamber configuration provides verylimited protection against vibration or agitation when tipped to oneside.

U.S. Pat. No. 3,597,280 to Hennen disclosed a multiple vent plugassembly for merely reducing spillage when a battery is partially tippedor completely inverted. The plug assembly incorporates a multi-chamberconfiguration designed to contain a substantial portion of electrolyteprior to spilling the electrolyte to atmosphere. The Hennen patent doesnot disclose a chamberless cover design or provide substantial leakprotection over extended periods of time.

U.S. Pat. No. 4,348,466 to Elehew et al. discloses a large rectangularchamber configuration having an inlet in communication with a respectivecell. Each chamber has an outlet off to one side of and below the inlet.A passage associated with the chamber outlet is provided for containingand holding electrolyte. The passage has an outlet in communication withan atmospheric vent. The arrangement is such that the chambers andassociated passages are of sufficient volume to retain the amount ofelectrolyte displaced into them when equilibrium is achieved betweenlevels of electrolyte in the cells and respective chambers and passages.

The Elehew et al. patent requires that a portion of the passage be abovethe chamber inlet regardless to which side the battery is tipped. Whenthe chambers and the passages fill with electrolyte, an airlock isdeveloped which prevents additional flow of electrolyte from the cellinto the chamber and passage configuration.

The Elehew et al. patent provides no leak protection when the battery isinverted and provides only steady state protection when the battery istipped to one side. As seen from viewing the chamber and passageconfiguration of the Elehew et al. patent, when a battery using theElehew et al. cover is tipped on various sides and vibrated or agitated,it is very likely that electrolyte will spill out of the chamber and runinto the passage to the venting area. The large chambers and passageconfiguration in Elehew et al. allows substantial amounts of electrolyteto spill into the battery cover; thus, increasing the likelihood ofelectrolyte being spilled into the venting area and ultimately leakingoutside the battery systems. The Elehew et al. patent is directedtowards preventing leak protection at a steady-state equilibrium whenthe battery is tipped to one side. Having substantial amounts ofelectrolyte in the cover and limited flow restriction substantiallyincreases the likelihood that electrolyte will spill if the battery isvibrated or agitated after arriving at an equilibrium in a non-uprightposition.

Similar configurations are shown in U.S. Pat. No. 5,380,604 to Hampe etal. and U.S. Pat. No. 5,424,146 to Lin. Both patents disclosed leakresistant battery covers having chambers associated with each cell. Thechambers have guides for controlling the flow of acid. However, eachcover is designed to allow a significant amount of electrolyte to flowinto the respective cover and provides no protection against electrolyteleakage when the battery is inverted and very limited protection whenvibrated or agitated.

The German Patent No. 4,216,563 discloses a dual section cover having achamber associated with each cell. Each chamber is sized so that whenthe battery is tipped or inverted, no more acid from a respective cellenters the gas collection chamber than the chamber can contain. Althoughthe German patent attempts to address inverted leak protection, allowingsuch substantial amounts of electrolyte to flow out of the cells andinto the cover substantially increase the risk of electrolyte leakingoutside of the battery system.

Aside from the above arrangements, far more complex arrangements areknown which are used on aircraft batteries and the like which not onlydeal with the problem of electrolyte flowing from the cell when tippedto any one of its sides, but also maintains the battery in operationwhen completely inverted. These designs are not cost effective for themajority of battery applications. Accordingly, there remains a need toprovide an anti-spill battery cover for liquid electrolyte batterieswhich is relatively inexpensive to manufacture, prevents spillage ofelectrolyte when tipped toward or onto any one of its sides, providesadditional resistance to spillage when vibrated or agitated while tippedtoward or on any one of its sides, and prevents spillage of electrolytewhen the battery is substantially or completely inverted. Furthermore,there is a need for a chamberless battery cover of limited volumecapable of forming an air-lock in a short period of time after tipped orinverted in order to minimize the amount of electrolyte entering thecover and significantly reducing the potential of electrolyte reachingan atmospheric vent. A need exists for a chamberless, leak resistantbattery cover using only one atmospheric vent in order to further reducethe likelihood of electrolyte spills. A need remains for a battery coverhaving the above features in order to prevent harm to person andproperty caused by contact with electrolyte or from the potential offire and explosion if exhaust gases are ignited.

SUMMARY OF THE INVENTION

The present invention is directed to a leak resistant battery cover forstorage batteries. The battery cover provides a labyrinth of passagesproviding a path from each cell vent to the atmospheric vent. Thelabyrinth is configured to provide a portion of each path above a levelin which the electrolyte in the respective cells attains when thebattery is tipped on any one of its sides or rotated ninety (90) degreesfrom an upright position. The labyrinth configuration preventselectrolyte from reaching the atmospheric vent and spilling out of thebattery.

The passages of the labyrinth may include portions extendinghorizontally from a passage wall towards the center of the passage.These horizontally extending passages are generally perpendicular to thepassage wall or angled in a manner obstructing the flow of electrolytetoward the atmospheric vent. Preferably, the horizontally extendingpassages alternate from opposing sides of the passage. The labyrinthconfiguration of the current invention provides improved leak protectionover the above discussed prior art when the battery is tipped to oneside. Additionally, the substantially convoluted passages provideinverted leak resistance.

The convoluted passages in conjunction with the partitions operate toform an air-lock between the cell vent and the atmospheric vent. Byproving such a convoluted path for air to travel, an air-lock is formedin the passages. When air is prevented from entering the battery,additional electrolyte is prevented from leaving each cell, entering thelabyrinth and ultimately leaking through the atmospheric vent.

The passages of the labyrinth may also include portions extendingvertically from a passage floor or ceiling. The vertically extendingpassages provide enhanced leak protection when the battery is inverted.Preferably, the vertically extending partitions alternate from the floorand ceiling and the portions extending from the ceiling aresubstantially longer than the partitions extending from the floor inorder to provide a greater electrolyte barrier when inverted. Thevertically extending partitions aid in forming an air-lock andpreventing air from entering the cells.

Accordingly, one aspect of the current invention is to provide a leakresistant battery cover for a lead acid battery of the type including ahousing having a plurality of cells containing electrolyte and aplurality of partition walls separating the cells. The cover includes(1) a cover having a floor and ceiling forming an interior areatherebetween, wherein the cover includes a bottom adjacent, the batteryhousing wherein the cover sealably engages in the housing and partitionwalls; (2) a plurality of cell vents in and extending through the bottomof the cover wherein each cell vent is adapted to communicate gaseswithin the corresponding cells of the battery to the interior area ofthe cover; (3) an atmospheric vent on the cover adapted to communicategases from within the interior area of the cover to atmosphere; (4) alabyrinth system between said floor and ceiling in the interior area ofthe cover form a plurality of narrow passages wherein the passagesformed of a plurality of convoluted paths communicating each cell ventto the atmospheric vent and each cell vent communicates substantiallyimmediately with one of the passage of the labyrinth; and (5) aplurality of cell drains on said floor and extending through the bottomof the cover wherein the cell drains communicate with the passages, andthe cell drains are adapted to communicate liquid in the passages torespective cells. The passages of the labyrinth are so arranged thateach of said paths has a branch above an electrolyte level for thecorresponding cell when the battery is rotated as much as ninety degreesfrom an upright position.

Another aspect of the current invention is to provide a labyrinthadapted to provide for two or more of the passages communicating witheach cell vent to converge into a common passage in the labyrinth priorto the atmospheric vent, wherein the path from each cell vent to theatmospheric vent is common for respective cells. Furthermore, all of thepassages communicating with each cell vent may converge into a finalcommon passage in the labyrinth prior to the atmospheric vent.

Still another aspect of the current invention is to provide a labyrinthhaving passages sloped towards the cell drains to allow liquidelectrolyte in the passages to flow into respective cells. Additionally,the cell vent and the cell drain are an integrated vent and drain backunit.

Another aspect of the current invention is to provide a labyrinth ofpassages which are substantially convoluted and substantially orentirely encircle each respective cell vent. Preferably, each path toatmosphere for each cell has a branch running substantially near aportion of the periphery of the cover.

Still another aspect of the current invention is to provide a labyrinthwherein each path formed by the passages form one path to atmosphere foreach cell. Various portions of each path may be common to another path.Additionally, the passages of the labyrinth may be adapted to provide apath from each cell vent to the atmospheric vent which crosses thelateral axis twice.

Another aspect of the current invention is to provide a battery coverhaving a transverse axis perpendicular to the lateral axis with passagesadapted to provide a path from each cell vent to the atmospheric venthaving a portion substantially along the transverse axis. Furthermore,the battery may have each cell vent, each cell drain and the atmosphericvent on one side of the lateral axis. Generally, the battery cover isadapted for a six cell lead acid battery wherein the battery coverincludes six cell vents, six cell drains and one atmospheric vent.Preferably, the battery cover is constructed of a lower cover portionand an upper cover portion. The lower and upper cover portions sealablyengage one another to form the labyrinth system.

Another aspect of the current invention is to provide a cover includinga second atmospheric vent wherein approximately half of the cell ventscommunicate with each atmospheric vent.

Yet another aspect of the current invention is to provide the passagesof the labyrinth with a plurality of horizontally extending partitionsextending into the passages to provide resistance to any flow of liquid,towards the atmospheric vent when the battery is toppled. Thehorizontally extending partitions extend from interior sides of thepassages of the labyrinth and are often slanted against a direction offlow of electrolyte toward the atmospheric vent to provide furtherresistance against the flow of liquid electrolyte towards theatmospheric vent when the battery is toppled. Preferably, thehorizontally extending partitions alternate from opposing interior sidesof the passages of the labyrinth.

Still another aspect of the current invention is to provide the passagesof the labyrinth with a plurality of vertically extending partitionsextending into the passages to provide resistance to the flow of liquidtowards the atmospheric vent. The vertically extending partitions aid inrestricting electrolyte flow in the passages and in providing an airlockbetween the cells and the atmospheric vent when the battery is inverted.The vertically extending partitions may extend from either an upper orlower portion of the passages. Preferably, the upper and lowervertically extending partitions alternate along the passage. Thevertically extending partitions extending from the upper portion of thepassage extend below a level in which the vertically extendingpartitions extending from the lower portion extend. The verticallyextending partitions provide an obstructed path along the passage.

Yet another aspect of the current invention is to provide the commonpassage of the labyrinth with a plurality of substantially verticallyextending partitions adapted to provide resistance to the flow of liquidtowards the atmospheric vent. The vertically extending partitions extendfrom an upper and lower portion of the common passage and alternatealong the common passage. The vertically extending partitions extendingfrom the upper portion of the common passage extend below a level inwhich the vertically extending partitions extending from the lowerportion extend. The partitions provide an obstructed path to theatmospheric vent. The vertically extending partitions extending from theupper and lower portions of the common passage are preferablysubstantially adjacent along the common passage.

Still another aspect of the current invention is to provide the commonpassage of the labyrinth with an entrance, wherein the entrance includesa vertically extending partition adapted to provide resistance to theflow of liquid towards the atmospheric vent. The vertically extendingpartition at the entrance further aids in providing an airlock betweenthe cells and the atmospheric vent when the battery is inverted.

Another aspect of the current invention is to provide a leak resistantbattery cover for a lead acid battery of the type including a housinghaving a plurality of cells containing electrolyte and a plurality ofpartition walls separating the cells, the cover includes: (1) a coverhaving floor and ceiling forming an interior area therebetween, whereinthe cover includes a bottom adjacent the battery housing wherein thecover sealably engages the housing and partition walls; (2) a pluralityof cell vents in and extending through the bottom of the cover whereineach cell vent is adapted to communicate gases within the correspondingcells of the battery to the interior area of the cover; (3) anatmospheric vent on the cover adapted to communicate gases from withinthe interior area of the cover to atmosphere; (4) a labyrinth systembetween said floor and ceiling in the interior area of the cover form aplurality of narrow passages wherein the passages form a plurality ofsubstantially convoluted paths to communicate each cell vent to theatmospheric vent wherein each cell vent communicates substantiallyimmediately with one passage of the labyrinth; and (5) a plurality ofcell drains on said floor and extending through the bottom of the coverwherein the cell drains communicate with the passages wherein the celldrains are adapted to communicate liquid in the passages to respectivecells, and the passages of the labyrinth are so arranged that each ofsaid paths has a branch above an electrolyte level for the correspondingcell when the battery is rotated as much as ninety degrees from anupright position, wherein the labyrinth is adapted to provide for two ormore of the passages communicating with each cell vent to converge intoa common passage in the labyrinth prior to the atmospheric vent whereinthe path from each cell vent to the atmospheric vent has a portion incommon with one or more other said paths.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a battery having a leak resistantbattery cover constructed according to the present invention.

FIG. 2 is a top view of the labyrinth of passages in an intermediatecover of a leak resistant battery cover constructed according to thepresent invention.

FIG. 3 is a bottom view of the labyrinth of passages in an outer coverof the leak resistant battery cover mating with the intermediate covershown in FIG. 2.

FIG. 4 is a top view of a second embodiment of an intermediate coverconstructed according to the present invention.

FIG. 5 is a bottom view of the labyrinth of passages in the outer coverof the leak resistant battery cover constructed according to the presentinvention.

FIG. 6 is a partial cross-sectional view of a joined intermediate andouter cover along live 6—6 illustrating the upper and lower verticallyextending partitions and the atmospheric vent constructed according tothe present invention.

FIG. 7 is a partial cross-sectional view of the intermediate cover,taken along line 7—7 shown in FIG. 2, for illustrating the slopingpassages of the labyrinth constructed according to the presentinvention.

FIG. 8 is a partial top perspective depicting electrolyte gas flowaccording to the present invention.

FIG. 9 is a partial cross-sectional view of a battery cover constructedaccording to the present invention illustrating electrolyte level in thelabyrinth of passages when the battery is tipped onto one side in thedirection of the arrow.

FIG. 10 is a partial cross-sectional view of a battery cover constructedaccording to the present invention illustrating electrolyte level in thelabyrinth of passages when the battery is tipped onto one side in thedirection of the arrow.

FIG. 11 is a partial cross-sectional view of a battery cover constructedaccording to the present invention illustrating electrolyte level in thelabyrinth of passages when the battery is tipped onto one side in thedirection of the arrow.

FIG. 12 is a partial cross-sectional view of a battery cover constructedaccording to the present invention illustrating electrolyte level in thelabyrinth of passages when the battery is tipped onto one side in thedirection of the arrow.

FIG. 13 is a top view of a third embodiment of an intermediate coverconstructed according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, like reference characters designate likeor corresponding parts throughout the several views. Also, in thefollowing description, it is to be understood that such terms as“forward”, “rearward”, “left”, “right”, “upwardly”, “downwardly”, andthe like are words of convenience and are not to be construed aslimiting terms.

Referring now to the drawings in general, and FIG. 1 in particular, itwill be understood that the illustrations are for the purpose ofdescribing a preferred embodiment of the invention and are not intendedto limit the invention thereto. As best seen in FIG. 1, a battery,generally designated 10, is shown constructed according to the presentinvention. The battery 10 includes three major subassemblies: a batteryhousing 12, an intermediate cover 14, and an outer cover 16. Theintermediate cover 14 is normally heat sealed or glued to housing 12 andthe outer cover 16 is normally heat sealed to the intermediate cover 14.The battery housing 12 typically includes a plurality of partitionedcells 18A-F which are substantially isolated from each other when thecovers 14, 16 are sealed onto the housing 12. Since the embodiments ofthe invention are directed towards providing a leak resistant batterycover it is understood that various types of venting devices may beincorporated in the leak resistant arrangement and thus particularventing arrangements are not described in detail.

The intermediate cover 14 and outer cover 16 are designed to form anenclosed labyrinth of passages 20 when the covers 14, 16 are joined.Turning now to FIG. 2, a top view of the intermediate cover 14 is shown.A cell vent 22 and cell drain 24 (shown in FIG. 3) are provided for eachbattery cell 18. Preferably, the drain 24 is an aperture in theintermediate cover 14 and the vent 22 is formed by a slotted tube 23A-Fextending downward from the outer cover 16 into and partially throughthe aperture forming the drain. This drain/vent technique isconventional in the art. The cell vent 22 allows for the escape ofelectrolyte from each cell 18 of the battery 10. In normal operation,the electrolyte gas will condense back into liquid form and drain backinto the cell 18 through the cell drain 24. Thus, in a typical 12-voltautomotive or vehicle battery 10, there are six cells 18A-F, cells vents22A-F, and cell drains 24A″F.

When electrolyte gas escapes through cell vent 22, it communicates intoan initial passage 26 of the labyrinth 20 through a passage entrance 28.Each cell 18 is associated with one initial passage 26A-F and onepassage entrance 28A-F. The initial passage 26 ultimately leads toatmosphere. Multiple initial passages 26A-F converge into a first commonpassage 30 at a first convergent point 32. Although there may be manyconvergent points, the first embodiment initially brings two passages26B-C, 26D-E together at the first convergent point 32A′, 32B′. Thepaths from the outermost initial passages 26A, 26F join at points 32A″and 32B″, respectively. Thus, the first common passages 30A′, 30B′ forma portion of the path to atmosphere for three cells 18A-C, 18D-F,respectively. The two first common passages 30A′, 30B′ ultimatelycombine to form a final common passage 34 at a final convergence point36. The path to atmosphere for each cell 18 is provided by the finalcommon passage 34. The final common passage 34 leads to atmosphere viaan atmospheric vent 38 placed near the end of the final common passage34. In the preferred embodiment, the atmospheric vent 38 is a porousdisk located on the outer cover 16.

The labyrinth of passages 20 is designed to form a very convoluted pathto atmosphere. The initial passages 26A-F substantially encircle theirrespective cell vents 22A-F, service ports 40A-F, and typically includesa portion substantially near and along the perimeter portion of thebattery prior to reaching the first convergent point 32. The perimeterportion of the electrolyte path may also be provided in the first commonpassage 30 after the first convergent point 32. It is important for thelabyrinth of passages 20 to form very convoluted paths prior to reachingthe atmospheric vent 38.

FIG. 4 shows a second embodiment of the battery cover constructedaccording to the present invention. As with the embodiment in FIG. 2,electrolyte gases escape through cell vents 122, communicate into aninitial passage 126 of the labyrinth 120 through a passage entrance 128and converges into a first common passage 130A, 130B at a firstconvergent point 132A, 132B. The three initial passages 126A-C, 126D-Ffor each side of the battery converge into the common passages 130A,130B, at convergence points 132A, 132B, respectively. The common passage130A ultimately combines with a similar common passage 130B from theother half of the battery to form a final common passage 134 at a finalconvergent point 136.

FIG. 13 shows yet a further cover embodiment. Similar to the earlierembodiments, the third embodiment allows electrolyte gas to escapethrough a cell vent 222 into an initial passage 226 through a passageentrance 228. In the third embodiment, the initial passages 226A, 226Band 226C converge into a first common passage at substantially the samepoint 232A, 232B. The first common passage 230A, representing the flowpath for one-half of the battery, converges with the first commonpassage 230B, representing the other half, into a final common passage234 at final convergent point 236. The third embodiment differs from theearlier embodiments in that the final common passage 234 ultimatelysplits into diverging passages 237A, 237B. Each diverging passage 237communicates with atmospheric vents 238A, 23813, respectively. Thisarrangement is preferred in dual atmospheric vent embodiments. Thehorizontal and vertical partitions are selectively optional in any ofthe embodiments.

Returning now to FIG. 4, located along the various passages 126, 130 and134 are a plurality of perpendicular horizontally extending partitions142 and angled horizontally extending partitions 144. The partitions142, 144 provide a substantially obstructed path for electrolyte gas orliquid along the passages 125, 130 and 134. The angled horizontallyextending partitions 144 are preferably angled against the direction ofelectrolyte flow towards the atmospheric vent 138. The horizontallyextending partitions 142, 144 extend from the side of the passages 126,130, 134 towards the center thereof. Preferably, these partitions 142,144 are arranged to alternate along the passages 126, 130, 134 toprovide more effective path obstruction without blocking the pathentirely. Furthermore, the horizontally extending partitions 142, 144are positioned in a manner ensuring that electrolyte condensate will notlodge between the partitions 142, 144 or anywhere along the electrolytepath to effectively block the electrolyte path while in normaloperation.

Referring to FIGS. 4 and 5, the electrolyte path may also include aplurality of upper vertically extending partitions 150 (shown only inFIG. 5) and lower vertically extending partitions 146 (shown only inFIG. 4) extending from an upper and lower portion of a passage,respectively. The upper vertically extending partitions 150 extenddownwardly from the upper portion of the passage 134 while the lowervertically extending partitions 146 extend upwardly from the passage134. Preferably, the vertically extending partitions 146, 150 arelocated along the final common passage 134 prior to reaching theatmospheric vent 138. Also, a lower vertically extending entrancepartition 152 may be placed at the final convergence point 136. Thevertically extending partitions 146, 150, 152 extend across the width ofthe entire passage 134. The vertically extending entrance partitions 152(shown only in FIG. 4) and the lower vertically extending partitions 146extend from the intermediate cover 114. The upper vertically extendingpartitions 150 extend from the outer cover 116 and between the lowervertically extending partitions 146 on the intermediate cover 114.

FIG. 6 depicts a cross-sectional view along the final common passage 134formed by joining the intermediate cover 114 with the outer cover 116.When the upper and lower vertically extending partitions 146, 150 arealternatingly positioned, a series of “up-and-overs” are formed alongthe electrolyte path. As depicted, the lower vertically extendingpartitions 146 and upper vertically extending partitions 150 extend pastthe ends of the respective partitions 146, 150. Preferably, the uppervertically extending partitions 150 extending from the outer cover 116are substantially longer than the lower vertically extending partitions146 extending from the intermediate cover 114. Having the verticallyextending partitions 146, 150 configured in this manner provides greaterelectrolyte leakage protection while inverted. Inverted leak protectionis discussed in further detail below. The final common passage 134extends along a transverse axis 154 bisecting the length of the battery.

As best seen in FIGS. 4 and 5, the upper portion of the intermediatecover 114 is configured to substantially mirror the lower portion of theouter cover 116 to form the labyrinth of passages 120 and the pluralityof various partitions placed throughout. Once the covers 114, 116 aresealed, the passages 126, 130, 134 seal and form enclosed paths.

The passages 126, 130, 134 which make up the path from the passageentrance 128 to the atmospheric vent 138 are configured to continuouslyslope from the atmospheric vent 138 to the respective drain hole 124A-Fof each cell 18A-F. This sloping configuration returns the electrolytecondensate back to the cells 18A-F after the electrolyte gas hascondensed back into a liquid during normal operation. The angledhorizontally extending partitions 144 are oriented in a mannerpreventing entrapment of electrolyte condensate during its return to acell 18A-F. FIG. 7 is a cross-sectional view of the initial passages126A and depicts the continuously sloped elevation of the initialpassage 126A as it substantially circles and re-circles the cell vent122 and service port 140.

As best seen in FIG. 8, in normal operation of the battery, electrolytegas will rise from the cells 18A-F and enter the initial passage 126A-Fthrough the passage entrance 128A-F. The arrows show the path theelectrolyte gas would take from each respective passage entrance 128A-Fof each cell 18A-F to the atmospheric vent 138. The arrows highlight thehighly convoluted path to atmosphere associated with each cell 18A-F.Note that the electrolyte will condense well before reaching theatmospheric vent 138. The path to atmosphere for the cells 18A-F notdepicted is a mirror image of the path for the cells 18A-F depicted inFIG. 8.

As best seen in FIGS. 9-12, the labyrinth of passages 120 is configuredto provide a path from each cell vent 122A-F and drain hole 124A-F tothe atmospheric vent 138. Each path is configured to have a portionabove the electrolyte level 162 when the battery is tipped to any one ofits sides 164, 166, 168 and 170 or up to ninety (90) degrees from anupright position.

Referring to FIG. 9 in particular, a partial cross-sectional view of thelabyrinth of passages 120 is shown when the battery is tipped onto side164. The effective electrolyte level in the cells 18A-F is shown at line162. When the battery 10 is tipped to one of its sides, electrolyte 160will spill into the initial passage 126A-F and any other passages, suchas the first common passage 130A, 130B, until an airlock is formed bythe electrolyte 160 blocking airflow from the atmospheric vent to thecell 18 and/or when the electrolyte 160 spilling into the labyrinth ofpassages 120 reaches a level equal to the electrolyte level 162 in thecells 18A-F. When the battery 10 is tipped onto side 164, theelectrolyte 160 remains in the initial passage 126A-F because theelectrolyte level in the cells 18A-F is below portions of the pathformed by the initial passage 126A-F.

FIG. 10 depicts the battery 10 tipped onto side 66. As can be seen, theinitial passage 126A-F provides a path above the electrolyte level 162in each cell 18A-F. Thus, the amount of electrolyte 160 spilling intothe labyrinth of passages 120 is stopped once a level equal to the levelof electrolyte in the cells 18A-F is reached.

FIG. 11 depicts the battery 10 tipped onto side 168. As can be seen, theelectrolyte level in each cell 18A-F is higher than the level at whichmost of the labyrinth of passages 120 is located. However, a path abovethe electrolyte level 162 is provided for each cell. Thus, theelectrolyte 160 will never reach a level higher than the electrolytelevel 162 in the cells 18A-F. In many instances, an airlock will beformed prior to the electrolyte 160 reaching the level shown in FIG. 11because of the very convoluted paths formed by the passages 126, 130,134. These paths provide a substantial hurdle for the electrolyte 160 toovercome in order to reach the atmospheric vent 138. Substantial leakprotection is accomplished even during agitation. Given the lack ofcontainment chambers and the use of convoluted, narrow paths applicants'invention provides significant leak protection over existing batterycovers.

FIG. 12 depicts the battery 10 tipped onto side 170. Again, the amountof electrolyte 160 spilled into the cover system is substantiallylimited to the initial passage 126A-F. A path above the cell electrolytelevel 162 traps the electrolyte 160. In order for the electrolyte 160 toreach the atmospheric vent, the battery 10 would have to undergosubstantial rotation and agitation. The amount of protection provided bythe applicants' invention far exceeds those of the prior art in aneconomical fashion. Not only is the side tipping protection greatlyenhanced over the prior art by the applicants' invention, the batterycover also provides substantial leak resistance in an inverted positionas well. When the battery covers 114, 116 include the upper and lowervertically extending partitions 146, 150, the covers 114, 116 arevirtually leak proof. The alternating vertically extending partitions146, 150 help develop an airlock between the cell 18A-F and atmosphericvent 138. The effect is further enhanced if the upper verticallyextending partitions 150 on the outer cover 116 are increased in length.Preferably, the vertically extending partitions 150 extend into the pathby more than 75% of the path height. The amount of extension for boththe lower and upper vertically extending partitions 146, 150 and thespacing between these partitions 146, 150 are such that liquidelectrolyte will not form an airlock when the battery is operating in anupright position.

The covers 114 and 116 provide substantial leak resistance in aninverted position without using the lower and upper vertically extendingpartitions 146, 150. When inverted, the intricate, convoluted pathsformed by the labyrinth of passages 120 in conjunction with the numerousalternating perpendicular and angled horizontally extending partitions142, 144 will provide a substantial airlock in the paths between thecells 18A-F and the atmospheric vent 138. As seen in FIGS. 4 and 5,ambient air entering the labyrinth of passages 120 will have substantialdifficulty in reaching the cells 18A-F through the various convolutedpaths associated therewith. Electrolyte will not enter the labyrinth ofpassages 120 from the cells 18A-F without air being transferred into thecells 18A-F. Thus, providing an extremely difficult path for air totravel through the electrolyte to the cells 18A-F will substantiallyreduce electrolyte flow from cells 18A-F.

Certain modifications and improvements will occur to those skilled inthe art upon a reading of the foregoing description. It should beunderstood that all such modifications and improvements have beendeleted herein for the sake of conciseness and readability but areproperly within the scope of the following claims.

We claim:
 1. A leak resistant battery cover for a lead acid battery ofthe type including a housing having at least one cell, said covercomprising: a) a cover having a top cover member and a bottom covermember forming an enclosed area therebetween; b) an aperture in anextending through said bottom cover member into a cell of the housing,said aperture adapted to communicate gases within the cell to saidenclosed area of said cover; c) an atmospheric vent in said coveradapted to communicate gases from within said enclosed area of saidcover to atmosphere; d) a labyrinth of passages formed by a convolutedarrangement of vertical walls extending between said bottom cover memberand top cover member within said enclosed area, said labyrinth forming afirst convoluted path between said aperture and said atmospheric vent;and e) said labyrinth being so arranged that at least one portion of thefirst convoluted path thereof is at a level above the electrolyte levelin said cell when the battery is rotated as much as ninety degrees froman upright position, no matter whether said battery is rotatedforwardly, rearwardly, or to either side.
 2. The apparatus according toclaim 1 wherein said bottom cover member includes a second aperturecommunicating with the housing and a second convoluted path between saidsecond aperture and said atmospheric vent, said labyrinth forming aportion of said second path wherein said first and second convolutedpaths have at least one common passage.
 3. The apparatus according toclaim 2 wherein said second convoluted path is at least partially formedby first additional convoluted walls extending between said top andbottom of said cover within said interior chamber.
 4. The apparatusaccording to claim 2 wherein said cover includes a third aperturecommunicating with the housing and a third convoluted path between saidthird aperture and said atmospheric vent, said labyrinth forming aportion of said third convoluted path wherein said second and thirdconvoluted paths have at least one common passage.
 5. The apparatusaccording to claim 4 wherein said third convoluted path is partiallyformed by second additional convoluted walls extending between said topand bottom of said cover within said interior chamber.
 6. The apparatusaccording to claim 1 wherein: said cover includes a second aperturecommunicating with the housing and a second path communicating saidsecond aperture to said atmospheric vent, said labyrinthine passageforming a portion of said second path wherein said convoluted path andsaid second path have a portion in common and said second path isconvoluted and at least partially formed by first additional convolutedand at least partially formed by first additional convoluted wallsextending between said top and bottom of said cover within said interiorchamber; and said cover includes a third aperture communicating with thehousing and a third path communicating said third aperture to saidatmospheric vent, said labyrinthine passage forming a portion of saidthird path wherein said convoluted path and said third path have aportion in common, and said third path is convoluted and at leastpartially formed by second additional convoluted walls extending betweensaid top and bottom of said cover within said interior chamber.
 7. Theapparatus according to claim 1 wherein said cover includes anotheraperture communicating with the housing and a second path communicatingsaid aperture to a second atmospheric vent, said labyrinthine passageforming a portion of said second path wherein said convoluted path andsaid second path have a portion in common.
 8. The apparatus according toclaim 1 wherein said cover includes a second aperture communicating withthe housing and a second labyrinthine passage formed by a secondconvoluted arrangement of vertical walls extending between said bottomand top of said cover within said interior area, said secondlabyrinthine passage forming a second convoluted path to communicatesaid aperture to a second atmospheric vent wherein said second aperturecommunicates substantially immediately with said second labyrinthinepassage.
 9. The apparatus according to claim 2 wherein all of saidconvoluted paths are arranged to converge into one final common passageprior to arriving at said atmospheric vent.
 10. The apparatus accordingto claim 1 wherein said passage and said bottom of said housing aresloped toward said aperture to allow liquid electrolyte in said path toflow into the cell.
 11. The apparatus according to claim 1 wherein saidaperture is a cell vent.
 12. The apparatus according to claim 1 whereinsaid aperture is a cell drain.
 13. The apparatus according to claim 1wherein said aperture is a cell drain and a vent.
 14. The apparatusaccording to claim 8 wherein said cell drain and said cell vent is anintegrated vent and drain back unit.
 15. The apparatus according toclaim 1 wherein said labyrinth includes a plurality of horizontallyextending partitions extending into said passage to provide resistanceto any flow of liquid towards said atmospheric vent when said battery istoppled.
 16. The apparatus according to claim 15 wherein saidhorizontally extending partitions extend from interior sides of at leastone of said passages.
 17. The apparatus according to claim 16 whereinsaid horizontally extending partitions are slanted against a directionof flow of electrolyte toward said atmospheric vent to provide furtherresistance against the flow of liquid electrolyte towards saidatmospheric vent when said battery is toppled.
 18. The apparatusaccording to claim 16 wherein said horizontally extending partitionsextend in alternate arrangement from opposing interior sides of saidpassage of said labyrinth.
 19. The apparatus according to claim 17wherein said horizontally extending partitions alternate from opposingsaid interior sides of said passages of said labyrinth.
 20. Theapparatus according to claim 1 wherein each of said paths substantiallyencircles its corresponding aperture.
 21. The apparatus according toclaim 1 wherein each of said paths completely encircles itscorresponding cell.
 22. The apparatus according to claim 1 wherein saidbattery cover is adapted for a six cell lead acid battery housing, saidbattery cover having six apertures and one said atmospheric vent, eachaperture having an associated convoluted path to said atmospheric vent.23. The apparatus according to claim 1 wherein said battery cover isconstructed of a lower cover portion and an upper cover portion, saidlower and upper cover portions sealably engaging one another to formsaid enclosed area and said labyrinth.
 24. The apparatus according toclaim 1 wherein said battery cover further includes a second atmosphericvent.
 25. The apparatus according to claim 1 wherein said passage has aportion running substantially near a portion of a periphery of saidcover.
 26. A leak resistant battery cover for a lead acid battery of thetype including a housing having a plurality of cells containingelectrolyte and a plurality of partition walls separating said cells,said cover comprising: (a) a floor including a plurality of cell ventsand cell drains, a ceiling including an atmospheric vent, and alabyrinth system of passages therebetween; (b) a floor and ceilingforming an interior area therebetween, said floor sealably engaging thehousing and partition walls; (c) said plurality of cell vents in andextending through said floor, each cell vent being adapted tocommunicate gases within a corresponding one of the cells of the batteryto said interior area of said cover, wherein each cell vent is a slottedvent extending from said ceiling through a corresponding one of saidcells drains in said flow, each cell vent having an opening therein tocommunicate gases from within a corresponding one of the cells of thebattery to said interior area of said cover; (d) said plurality of celldrains in and extending through said floor which communicate with saidpassages and communicate liquid electrolytes in said passages torespective cells; (e) an atmospheric vent in said cover adapted tocommunicate gases from said interior area of said cover to atmosphere;(f) said labyrinth system being between said floor and said ceiling insaid interior area of said cover formed of a plurality of passages, saidpassages forming a plurality of substantially convoluted paths tocommunicate each of said cell vents to said atmospheric vent, whereineach said cell vent communicates substantially immediately with one saidpassage of said labyrinth system; (g) wherein an initial passageway isformed around each vent opening by walls substantially encircling andimmediately adjacent each respective cell vent in which electrolyteescaping from said cell vent at times when the battery is in anon-upright position can collect, each of said initial passagewayssubstantially encircling a corresponding vent opening and communicatingwith at least one first common passage, said at least one first commonpassage communicating with a final common passage such that said finalcommon passage is in communication with each of said plurality of cellsand with said atmospheric vent; and (h) said passages of said labyrinthsystem being so arranged that each of said convoluted paths has at leastone portion above the level of the liquid electrolyte level for thecorresponding cell when the battery is rotated as much as ninety degreesfrom an upright position.
 27. The cover according to claim 26 wherein atleast one of said common passages includes a plurality of generallyhorizontally extending partitions extending into said passage to provideresistance to any flow of liquid electrolyte towards said atmosphericvent.
 28. The cover according to claim 26 wherein at least one of saidcommon passages includes a plurality of angled generally horizontallyextending partitions extending into said passage to provide resistanceto any flow of liquid electrolyte toward said atmospheric vent.
 29. Thecover according to claim 27 wherein at least one of said common passagesincludes a plurality of angled generally horizontally extendingpartitions extending into said passage to provide resistance to any flowof liquid electrolyte toward said atmospheric vent.
 30. The coveraccording to claims 26, 27, 28, or 29 wherein at least one of saidcommon passages includes a plurality of upper generally verticallyextending partitions and lower generally vertically extendingpartitions, said upper and lower partitions extending from respectiveupper and lower portions of said passage, said partitions forming anupwardly and downwardly directed convoluted path.
 31. The coveraccording to claims 26, 27, 28, or 29 wherein said initial passagewaysand common passageways slope downwardly from said atmospheric vent tosaid cell drains.
 32. The cover according to claim 30 wherein saidinitial passageways and common passageways slope downwardly from saidatmospheric vent to said cell drains.